class_docstr: HParams Plugin for TensorBoard.
  
  It supports both GETs and POSTs. See 'http_api.md' for more details.
code: def list_metric_evals_route(self, request):
      ctx = plugin_util.context(request.environ)
      experiment_id = plugin_util.experiment_id(request.environ)
      try:
          request_proto = _parse_request_argument(
              request, api_pb2.ListMetricEvalsRequest
          )
          scalars_plugin = self._get_scalars_plugin()
          if not scalars_plugin:
              raise werkzeug.exceptions.NotFound(
                  "Scalars plugin not loaded"
              )
          return http_util.Respond(
              request,
              list_metric_evals.Handler(
                  ctx, request_proto, scalars_plugin, experiment_id
              ).run(),
              "application/json",
          )
      except error.HParamsError as e:
          logger.error("HParams error: %s" % e)
          raise werkzeug.exceptions.BadRequest(description=str(e))
  
imports: import json
  import werkzeug
  from werkzeug import wrappers
  from tensorboard import plugin_util
  from tensorboard.plugins.hparams import api_pb2
  from tensorboard.plugins.hparams import backend_context
  from tensorboard.plugins.hparams import download_data
  from tensorboard.plugins.hparams import error
  from tensorboard.plugins.hparams import get_experiment
  from tensorboard.plugins.hparams import list_metric_evals
  from tensorboard.plugins.hparams import list_session_groups
  from tensorboard.plugins.hparams import metadata
  from google.protobuf import json_format
  from tensorboard.backend import http_util
  from tensorboard.plugins import base_plugin
  from tensorboard.plugins.scalar import metadata
  from tensorboard.util import tb_logging
label_desc: Use image node_id 8 for calling the HParamsPlugin obj's underlying member method code with example usage: obj.list_metric_evals_route(request) and returns: http_util